Various kinds of web threading apparatus are used both in web-fed rotary printing machines and in other paper handling machines in the paper industry. As a rule, they include guides extendling laterally beside a long edge of the web, along the intended threading course, with a pulling or threading element movable within these guides. A catch of some kine is secured to the pulling element and extends over a portion of the width of the web.
For securing the web to the catch, provisions have heretofore been made for tapering the leading end of the web to a point in the threading direction and then securing it by means of adhesive tapes or paster tabs to a loop to be attached to the catch. In order to prevent edge tearing of the web, its longitudinal edges were additionally reinforced with adhesive tapes in the tapered area. Since these operations must be performed on the end of the web suspended freely in the air between the supply roll and the rollers of the machine into which the web is to be threaded, they are time consuming, and should they be inexpertly performed they can easily result in loosening of the paster tabs during the threading operation.